fix(ledger): re-export canonicalJson from ledger-anchor.ts (#9270)

Lost during editing -- the re-export line only carried sha256Hex, so any
consumer importing canonicalJson from this module got undefined. Caught while
building #9273's git-commit backend, which needs it to commit the same
canonicalized payload Rekor anchors.

Author: JSONbored

src/review/ledger-anchor.ts

@@ -211,4 +211,7 @@ export function anchorKeyById(keys: readonly AnchorPublicKey[], keyId: string):
 }
 
 /** Digest helper re-exported so an anchor consumer never needs a second import just to hash a payload. */
-export { sha256Hex };
+/** Digest helpers re-exported so an anchor consumer (e.g. the git-commit backend, #9273, which commits the
+ *  same canonicalized payload Rekor anchors) never needs a second import from decision-record.ts just to
+ *  canonicalize or hash something alongside a signed anchor. */
+export { canonicalJson, sha256Hex };